envspew example

.envrc

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+eval "$(lorri direnv)"

cmd/web/main.go

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+package main
+
+import (
+	"encoding/json"
+	"net/http"
+	"os"
+	"time"
+)
+
+type config map[string]interface{}
+
+func envOr(name, val string) string {
+	if result := os.Getenv(name); result != "" {
+		return result
+	}
+
+	return val
+}
+
+func loadConfig(cfg config) error {
+	fin, err := os.Open(envOr("CONFIG_PATH", "./envspew.json"))
+	if err != nil {
+		return err
+	}
+	defer fin.Close()
+
+	return json.NewDecoder(fin).Decode(&cfg)
+}
+
+func main() {
+	cfg := config{}
+	loadConfig(cfg)
+	cfg["now"] = time.Now().String()
+
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		json.NewEncoder(w).Encode(cfg)
+	})
+
+	http.ListenAndServe(":"+envOr("PORT", "9001"), nil)
+}

default.nix

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+{sources ? import ./nix/sources.nix, pkgs ? import sources.nixpkgs { } }:
+
+let
+  envspew = pkgs.buildGoPackage {
+    name = "envspew";
+    goPackagePath = "tulpa.dev/cadey/envspew";
+    src = ./.;
+    allowGoReference = false;
+    preBuild = ''
+      export CGO_ENABLED=0
+      buildFlagsArray+=(-pkgdir "$TMPDIR")
+    '';
+  };
+in pkgs.dockerTools.buildLayeredImage {
+  name = "xena/envspew";
+  contents = [ envspew ];
+  config.Cmd = [ "/bin/web" ];
+}

envspew.json

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+{"TODAY": "is gonna be the day", "THAT_IM": "gonna bring it back to you"}

envspew.yml

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+kind: Namespace
+apiVersion: v1
+metadata:
+  name: envspew
+---
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: envspew
+  namespace: envspew
+data:
+  config.json: |
+    {
+      "WERE_NO": "strangers to love",
+      "YOU_KNOW": "the rules and so do i"
+    }
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: envspew
+  namespace: envspew
+  annotations:
+    reloader.stakater.com/auto: "true"
+spec:
+  replicas: 2
+  selector:
+    matchLabels:
+      app: envspew
+  template:
+    metadata:
+      labels:
+        app: envspew
+    spec:
+      volumes:
+        - name: config
+          configMap:
+            name: envspew
+      containers:
+        - name: web
+          image: xena/envspew:n2ws8s1i02j0n14xxz7993sxb5ff382n
+          ports:
+            - containerPort: 9001
+          env:
+            - name: CONFIG_PATH
+              value: /cfg/config.json
+          volumeMounts:
+            - name: config
+              mountPath: /cfg
+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: envspew
+  namespace: envspew
+  labels:
+    app: envspew
+spec:
+  ports:
+    - port: 9001
+      targetPort: 9001
+---
+kind: Ingress
+apiVersion: networking.k8s.io/v1beta1
+metadata:
+  name: envspew
+  namespace: envspew
+  labels:
+    app: envspew
+  annotations:
+    kubernetes.io/ingress.class: nginx
+spec:
+  rules:
+    - host: envspew.local.cetacean.club
+      http:
+        paths:
+          - backend:
+              serviceName: envspew
+              servicePort: 9001
+

go.mod

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+module tulpa.dev/cadey/envspew
+
+go 1.14
+
+require github.com/rogpeppe/go-internal v1.5.2 // indirect

go.sum

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+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/rogpeppe/go-internal v1.5.2 h1:qLvObTrvO/XRCqmkKxUlOBc48bI3efyDuAZe25QiF0w=
+github.com/rogpeppe/go-internal v1.5.2/go.mod h1:xXDCJY+GAPziupqXw64V24skbSoqbTEfhy4qGm1nDQc=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=

nix/sources.json

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+{
+    "niv": {
+        "branch": "master",
+        "description": "Easy dependency management for Nix projects",
+        "homepage": "https://github.com/nmattia/niv",
+        "owner": "nmattia",
+        "repo": "niv",
+        "rev": "f73bf8d584148677b01859677a63191c31911eae",
+        "sha256": "0jlmrx633jvqrqlyhlzpvdrnim128gc81q5psz2lpp2af8p8q9qs",
+        "type": "tarball",
+        "url": "https://github.com/nmattia/niv/archive/f73bf8d584148677b01859677a63191c31911eae.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs": {
+        "branch": "nixos-20.03",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "29eddfc36d720dcc4822581175217543b387b1e8",
+        "sha256": "1gqv2m7plkladd3va664xyqb962pqs4pizzibvkm1nh0f4rfpxvy",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/29eddfc36d720dcc4822581175217543b387b1e8.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "xepkgs": {
+        "branch": "master",
+        "description": "Xe's packages",
+        "homepage": "",
+        "owner": "Xe",
+        "repo": "xepkgs",
+        "rev": "b781bddd6a0f0db266637431a4663150ed5c1927",
+        "sha256": "0dbxy3sgndb3934ci39ib18pz5zi53cfhd75p6c9gr3fy4lni7qk",
+        "type": "tarball",
+        "url": "https://github.com/Xe/xepkgs/archive/b781bddd6a0f0db266637431a4663150ed5c1927.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    }
+}

nix/sources.nix

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+# This file has been generated by Niv.
+
+let
+
+  #
+  # The fetchers. fetch_<type> fetches specs of type <type>.
+  #
+
+  fetch_file = pkgs: spec:
+    if spec.builtin or true then
+      builtins_fetchurl { inherit (spec) url sha256; }
+    else
+      pkgs.fetchurl { inherit (spec) url sha256; };
+
+  fetch_tarball = pkgs: spec:
+    if spec.builtin or true then
+      builtins_fetchTarball { inherit (spec) url sha256; }
+    else
+      pkgs.fetchzip { inherit (spec) url sha256; };
+
+  fetch_git = spec:
+    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
+
+  fetch_builtin-tarball = spec:
+    builtins.trace
+      ''
+        WARNING:
+          The niv type "builtin-tarball" will soon be deprecated. You should
+          instead use `builtin = true`.
+
+          $ niv modify <package> -a type=tarball -a builtin=true
+      ''
+      builtins_fetchTarball { inherit (spec) url sha256; };
+
+  fetch_builtin-url = spec:
+    builtins.trace
+      ''
+        WARNING:
+          The niv type "builtin-url" will soon be deprecated. You should
+          instead use `builtin = true`.
+
+          $ niv modify <package> -a type=file -a builtin=true
+      ''
+      (builtins_fetchurl { inherit (spec) url sha256; });
+
+  #
+  # Various helpers
+  #
+
+  # The set of packages used when specs are fetched using non-builtins.
+  mkPkgs = sources:
+    let
+      sourcesNixpkgs =
+        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) {};
+      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
+      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
+    in
+      if builtins.hasAttr "nixpkgs" sources
+      then sourcesNixpkgs
+      else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
+        import <nixpkgs> {}
+      else
+        abort
+          ''
+            Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
+            add a package called "nixpkgs" to your sources.json.
+          '';
+
+  # The actual fetching function.
+  fetch = pkgs: name: spec:
+
+    if ! builtins.hasAttr "type" spec then
+      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
+    else if spec.type == "file" then fetch_file pkgs spec
+    else if spec.type == "tarball" then fetch_tarball pkgs spec
+    else if spec.type == "git" then fetch_git spec
+    else if spec.type == "builtin-tarball" then fetch_builtin-tarball spec
+    else if spec.type == "builtin-url" then fetch_builtin-url spec
+    else
+      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
+
+  # Ports of functions for older nix versions
+
+  # a Nix version of mapAttrs if the built-in doesn't exist
+  mapAttrs = builtins.mapAttrs or (
+    f: set: with builtins;
+    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
+  );
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball = { url, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchTarball;
+    in
+      if lessThan nixVersion "1.12" then
+        fetchTarball { inherit url; }
+      else
+        fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl = { url, sha256 }@attrs:
+    let
+      inherit (builtins) lessThan nixVersion fetchurl;
+    in
+      if lessThan nixVersion "1.12" then
+        fetchurl { inherit url; }
+      else
+        fetchurl attrs;
+
+  # Create the final "sources" from the config
+  mkSources = config:
+    mapAttrs (
+      name: spec:
+        if builtins.hasAttr "outPath" spec
+        then abort
+          "The values in sources.json should not have an 'outPath' attribute"
+        else
+          spec // { outPath = fetch config.pkgs name spec; }
+    ) config.sources;
+
+  # The "config" used by the fetchers
+  mkConfig =
+    { sourcesFile ? ./sources.json
+    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
+    , pkgs ? mkPkgs sources
+    }: rec {
+      # The sources, i.e. the attribute set of spec name to spec
+      inherit sources;
+
+      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
+      inherit pkgs;
+    };
+in
+mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }

shell.nix

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+let
+  sources = import ./nix/sources.nix;
+  pkgs = import sources.nixpkgs { };
+  xepkgs = import sources.xepkgs { inherit pkgs; };
+in pkgs.mkShell {
+  buildInputs = with pkgs; [
+    go
+    goimports
+    kubectl
+    dive
+
+    xepkgs.gopls
+  ];
+}